A broadband millimeter-wave stripline flat panel array antenna

Abstract

The present invention discloses a broadband millimeter-wave stripline planar array antenna, comprising: a first dielectric substrate, a second dielectric substrate, and a third dielectric substrate laminated together in sequence, and metallized through-holes extending through each dielectric substrate; a first copper-clad floor is provided on the lower surface of the first dielectric substrate, a stripline power-splitting copper-clad layer is provided on the lower surface of the second dielectric substrate, and a second copper-clad floor is provided on the upper surface of the second dielectric substrate; a third copper-clad floor is provided on the upper surface of the third dielectric substrate, and second and third slots are provided on the second and third copper-clad floors, respectively, corresponding to the power-splitting terminals of the stripline power-splitting copper-clad layers; each power-splitting terminal, the corresponding second and third slots, and the metallized through-holes surrounding the three components together form an antenna unit. The present invention has the advantages of broadband, planarity, high gain, low processing cost, and ease of mass production.

Description

Technical Field

[0001] The present invention relates to the field of antenna design, and in particular to a broadband millimeter-wave stripline flat panel array antenna. Background Art

[0002] As modern communications continue to demand higher communication speeds, higher-frequency microwave millimeter-wave bands are increasingly being used in high-capacity communication scenarios. High-gain antennas are the front-end of wireless microwave communications, and their performance directly impacts overall communication quality. Traditional high-gain microwave antennas include variations of parabolic antennas, such as parabolic and Cassegrain antennas. However, these traditional antennas require longitudinal thickness to achieve the parabolic surface. For scenarios requiring low profiles and planarity, planar high-gain antennas are needed for aesthetics, weight reduction, and space savings. Traditional parabolic antennas are insufficient.

[0003] A common method for achieving planar high-gain antennas is to use planar antenna elements to form a two-dimensional array. The main processing methods include metal waveguide array antennas and printed circuit array antennas. Antennas using metal waveguides offer the advantages of low loss and wide bandwidth. However, they require machining to ensure precision, resulting in complex processes, low production efficiency, and high costs. Printed circuit antenna arrays can use planar printed circuit (PCB) processing, which offers high precision and low cost, making them suitable for the design and production of millimeter-wave high-gain antennas. Stripline structures, with their metal floor coverings above and below, have less radiated leakage energy than microstrip structures, resulting in less loss and less impact on the radiation pattern. This makes them suitable for array designs with stringent performance requirements for bandwidth and radiation pattern.

[0004] The difficulty with stripline array antennas lies in the large number of laminated dielectric plates used and the potential for blind hole processing, which increases the overall cost of the antenna. Reducing the number of dielectric plates and using through-hole processing could significantly reduce costs, facilitating the widespread application of this type of antenna.

[0005] Based on the above background, a broadband millimeter-wave stripline flat-panel array antenna is needed in practical applications to meet the requirements of broadband, planarization, high gain, and low processing cost in some scenarios of modern millimeter-wave communications. Summary of the Invention

[0006] The object of the present invention is to provide a millimeter-wave stripline planar array antenna that is broadband, high-gain, planar, low-cost, and easy to mass-produce.

[0007] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions.

[0008] A broadband millimeter-wave stripline planar array antenna comprises: a first dielectric substrate, a second dielectric substrate, and a third dielectric substrate laminated together in sequence, and metallized through-holes extending through each of the dielectric substrates; characterized in that a first copper-clad floor is provided on the lower surface of the first dielectric substrate, a stripline power-splitting copper-clad layer is provided on the lower surface of the second dielectric substrate, and a second copper-clad floor is provided on the upper surface of the second dielectric substrate; the stripline power-splitting copper-clad layer, the first copper-clad floor, and the second copper-clad floor together constitute a stripline transmission line; a third copper-clad floor is provided on the upper surface of the third dielectric substrate, and second and third slots are provided on the second and third copper-clad floors, respectively, corresponding to power splitter terminals of the stripline power-splitting copper-clad layer; each power splitter terminal, the corresponding second and third slots, and the metallized through-holes arranged around the periphery of the three together constitute an antenna unit.

[0009] More preferably, the antenna units form a periodically arranged array of 2×2 or more.

[0010] More preferably, a feeding waveguide is installed at the bottom of the first dielectric substrate, a first slot without copper cladding is provided at the center of the first copper cladding layer, and a tuning patch is provided at the center of the first slot; the first slot, the stripline power splitter copper cladding layer, and the portion of the metallized through hole at the center of the first dielectric substrate together constitute a resonant cavity, which is used to achieve high-efficiency conversion of electromagnetic energy from the feeding waveguide to the resonant cavity and then to the stripline power splitter copper cladding layer.

[0011] More preferably, the first slot is located at the center of the contact surface between the feeding waveguide and the first dielectric substrate.

[0012] More preferably, the stripline power dividing copper clad layer is a power dividing network composed of multiple groups of T-shaped stripline power dividing structures with the same phase, which is used to achieve equal-phase power distribution from the middle feeding waveguide to each of the antenna units; by adjusting the size of each group of T-shaped stripline power dividing structures, unequal power distribution from the center antenna unit to the edge antenna unit can be achieved.

[0013] More preferably, the stripline power divider copper clad layer achieves a uniform 1 dB power drop from the center antenna to the edge antenna units in the horizontal and vertical directions.

[0014] More preferably, the second gap and the third gap are both rectangular gaps, the opening size of the second gap is smaller than the opening size of the third gap, and the orthographic projection of the second gap on the third copper clad layer floor falls within the third gap.

[0015] More preferably, the portion of the metallized through hole surrounding the second gap in the first dielectric substrate and the second dielectric substrate forms a resonant cavity with the first copper-clad floor and the second copper-clad floor, which is used to realize electromagnetic energy conversion and couple the electromagnetic energy fed by the power splitter end to the third dielectric substrate.

[0016] More preferably, the portion of the metallized through hole surrounding the third slot in the third dielectric substrate and the second copper-clad layer ground plane form an open horn for radiating the electromagnetic energy coupled from the second slot into free space, thereby realizing conversion of radiation waves.

[0017] More preferably, the broadband millimeter-wave stripline planar array antenna is a millimeter-wave antenna operating at 20 GHz to 30 GHz.

[0018] The beneficial effects that can be achieved by the present invention using the above technical solutions are:

[0019] The three-layer dielectric substrate organically combines the gapped copper-clad floor, the stripline power divider copper-clad layer, and the metallized through-holes. In actual application, it is only necessary to design and adjust the gap size of each copper-clad floor, the layout of the stripline power divider copper-clad layer, and the position of the metallized through-holes to achieve broadband, high-gain, and planar millimeter-wave antennas. It can be used in broadband millimeter-wave high-gain antenna scenarios. At the same time, the antenna can be processed using low-cost PCB processing technology, which is easy to mass-produce. In addition, the antenna only uses three layers of dielectric substrate and metallized through-holes, which reduces the processing cost and difficulty compared to solutions with more layers of dielectric substrate and metallized blind hole processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is an overall schematic diagram of the broadband millimeter-wave stripline planar array antenna provided by the present invention.

[0021] Figure 2 This is a side view of the broadband millimeter-wave stripline flat panel array antenna provided by the present invention.

[0022] Figure 3 Schematic diagram of the structure of the waveguide to stripline transition area.

[0023] Figure 4 Schematic diagram of the copper layer of the stripline power divider.

[0024] Figure 5 Schematic diagram of the local stripline power divider copper layer.

[0025] Figure 6 This is a partial schematic diagram of the upper surface of the second copper clad layer.

[0026] Figure 7This is a partial schematic diagram of the upper surface of the third copper clad layer.

[0027] Figure 8 A frequency curve of return loss of an antenna provided in one embodiment of the present invention.

[0028] Figure 9 A graph showing how the gain of an antenna varies with frequency according to one embodiment of the present invention.

[0029] Figure 10 The magnetic field plane radiation pattern of the center frequency of the antenna provided by one embodiment of the present invention.

[0030] Figure 11 The electric field radiation pattern of the center frequency of the antenna provided by one embodiment of the present invention.

[0031] Description of reference numerals:

[0032] 1: Feed waveguide, 2: First copper-clad floor, 3: Stripline power divider copper-clad layer, 4: Second copper-clad floor, 5: Third copper-clad floor, 61: First dielectric substrate, 62: Second dielectric substrate, 63: Third dielectric substrate, 7: Metallized through hole.

[0033] 201: first slot, 202: tuning patch, 301: power splitter end, 401: second slot, 501: third slot.

[0034] 311, 321, 331, 341: points. DETAILED DESCRIPTION

[0035] In the description of the present invention, it should be noted that, for directional words, such as the terms "center", "horizontal", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and so on, indicating directions and positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and cannot be understood as limiting the specific scope of protection of the present invention.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features. Therefore, the terms "first" and "second" may explicitly or implicitly include one or more of these features. Throughout the description of the present invention, "at least" means one or more than one, unless otherwise specifically defined.

[0037] In the present invention, unless otherwise specified or limited, the terms "assemble," "connect," and "connect" should be understood in a broad sense. For example, they may refer to fixed connection, detachable connection, or integral connection; mechanical connection; direct connection, connection through an intermediate medium, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0038] In the present invention, unless otherwise specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature therebetween. Furthermore, a first feature being "above," "below," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "above," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0039] The following description of the embodiments of the present invention is further described in conjunction with the accompanying drawings to make the technical solutions and beneficial effects of the present invention clearer and more specific. The following description of the embodiments with reference to the accompanying drawings is illustrative and intended to explain the present invention, but is not to be construed as limiting the present invention.

[0040] Additional aspects and advantages of the invention will become apparent from the description which follows, or may be learned by practice of the invention.

[0041] like Figure 1 As shown, a broadband millimeter-wave stripline planar array antenna includes: a first dielectric substrate 61, a second dielectric substrate 62, and a third dielectric substrate 63 laminated together in sequence, and a metallized through-hole 7 penetrating each of the dielectric substrates; a first copper-clad floor 2 is provided on the lower surface of the first dielectric substrate 61, a stripline power-splitting copper-clad layer 3 is provided on the lower surface of the second dielectric substrate 62, and a second copper-clad floor 4 is provided on the upper surface of the second dielectric substrate 62. The stripline power-splitting copper-clad layer 3 and the first copper-clad floor 4 are connected to each other. The board 2 and the second copper-clad floor 4 together constitute a strip transmission line; a third copper-clad floor 5 is provided on the upper surface of the third dielectric substrate 63, and a second slot 401 and a third slot 501 corresponding to each power splitter terminal 301 of the stripline power splitter copper clad layer 3 are respectively provided on the second copper-clad floor 4 and the third copper-clad floor 5. Each power splitter terminal 301, the corresponding second slot 401, the third slot 501 and the metallized through-hole 7 arranged around the periphery of the three together constitute an antenna unit.

[0042] The specific structures of the first copper-clad floor panel 2 , the second copper-clad floor panel 4 and the third copper-clad floor panel 5 are as follows: the copper-clad layers cover the entire corresponding surfaces of the dielectric substrate except for corresponding gaps.

[0043] The first dielectric substrate 61, the second dielectric substrate 62, and the third dielectric substrate 63 serve as carriers for the copper cladding layers. Copper cladding layers can be processed on the upper and lower surfaces of each dielectric substrate. Depending on actual processing requirements, thinner prepregs can be added between adjacent dielectric substrates to facilitate lamination.

[0044] The metallized vias 7 penetrate all dielectric substrates and, according to the design layout, enable electrical connection between the first copper-clad floor 2, the second copper-clad floor 4, and the third copper-clad floor 5. The metallized vias 7 are spaced apart from the stripline power splitter copper clad 3 and are not electrically connected. The metallized vias 7 limit the lateral diffusion of electromagnetic waves within their range, achieving efficient resonant cavity coupling and electromagnetic wave radiation. This facilitates efficient energy conversion from waveguide to stripline power splitter copper clad, energy coupling from the stripline power splitter copper clad to the open-ended horn, and energy conversion from the open-ended horn to space-radiated waves.

[0045] Combine Figure 2 、 Figure 3 As shown, a feed waveguide 1 is mounted on the bottom of the first dielectric substrate 61. A first, non-copper-clad slot 201 is provided at the center of the first copper-clad layer 2. A tuning patch 202 is provided at the center of the first slot 201. The feed waveguide 1 is mated and connected to the first slot 201 and the tuning patch 202. In this embodiment, the non-copper-clad first slot 201 is etched in the center of the first copper-clad metal layer 2 and located at the center of the interface between the feed waveguide 1 and the first dielectric substrate. The first slot 201, the stripline power splitter copper layer 3, and the metallized through-hole 7 at the center of the first dielectric substrate 61 together form a resonant cavity. Through optimization and adjustment, this allows for highly efficient conversion of electromagnetic energy from the feed waveguide 1 to the resonant cavity and then to the stripline power splitter copper layer 3.

[0046] Combine Figure 4 As shown, the stripline power splitter copper layer 3 forms a power splitting network composed of multiple sets of in-phase T-shaped stripline power splitter structures, achieving equal phase power distribution from the central feed waveguide 1 to each antenna unit. Each antenna unit receives power from the power splitter network and radiates electromagnetic waves. By adjusting the size of each set of T-shaped stripline power splitters according to power distribution requirements, unequal power distribution can be achieved from the center antenna unit to the edge antenna units. Figure 5A schematic diagram of a local 4×4 power splitter network is further provided. As can be seen from the figure, the 4×4 power splitter network consists of four T-type power splitters 311, 321, 331, and 341. Each power splitter can be independently sized to achieve the desired power distribution, based on design requirements. Power splitter 321 has a bend to achieve equal phase power splitting between antenna elements while avoiding the need for nearby metallized vias 7.

[0047] Combine Figure 6 The figure shows a schematic diagram of the local 4×4 distribution of second slots 401. The overall distribution of second slots 401 on the second copper-clad floor plate 4 is similar. For the local unit, the portion of the metallized through-hole 7 surrounding the second slots 401 within the first and second dielectric substrates 61 and 62 forms a resonant cavity with the first and second copper-clad floor plates 2 and 4, enabling electromagnetic energy conversion. The second copper-clad floor plate 4 serves as the unit coupling layer. After optimized dimensions, the second slots 401 can couple the electromagnetic energy fed from the power splitter terminal 301 to the third dielectric substrate 63.

[0048] Combine Figure 7 The figure shows a schematic diagram of the local 4×4 distribution of third slots 501. The overall array distribution of third slots 501 on the third copper-clad floor 5 can be analogously applied. For the local unit, the portion of the metallized through-hole 7 surrounding the third slots 501 within the third dielectric substrate 63 and the second copper-clad floor 4 can be equivalent to an open horn, radiating electromagnetic energy coupled from the second slots 401 into free space, thereby converting the radiated wave. By adjusting the dimensions of each component, a high-gain millimeter-wave array antenna with directional radiation can be achieved.

[0049] According to one embodiment of the present application, a broadband millimeter-wave stripline planar array antenna designed to operate at 30 GHz is designed. The first, second, and third dielectric substrates 61, 63 all feature a relative permittivity of 3.0 and a loss tangent of 0.003. The thicknesses of the first and second dielectric substrates 61, 62, and 63 are 0.529 mm, respectively, while the thickness of the third dielectric substrate 63 is 1.542 mm. Each dielectric substrate measures 150 mm x 150 mm. A 0.1 mm thick prepreg is placed between adjacent dielectric substrates for lamination. The electric field of the antenna radiation field is oriented along the short side of the slot, while the magnetic field is oriented along the long side of the slot. The periodic distance between the elements of the array is 8.5 mm in both directions. The dimensions of the first rectangular slot 401 are 3.1 mm x 0.6 mm, and those of the second rectangular slot 501 are 5.0 mm x 3.25 mm. The diameter of the metallized through-hole 7 is 0.5mm. In the unit part, the distance between two adjacent metallized through-holes 7 is 1mm, and the distance between diagonal metallized through-holes 7 is 6.0mm×4mm. The antenna uses a standard waveguide BJ260 for feeding. The parameters of the waveguide to stripline conversion structure are: the outer contour dimensions of the annular gap 201 are 7.6mm×3.7mm, and the dimensions of the center tuning patch are 4mm×1.8mm. In order to reduce side lobes, the stripline power divider copper layer 3 can achieve a uniform 1dB power drop in the horizontal and vertical directions from the center to the edge unit. The dimensions of the T-type power divider in each part are adjusted independently of each other and will not be repeated here.

[0050] Based on the same design principle as above, by adjusting the dimensions of each part, in other implementations, various broadband millimeter-wave stripline flat panel array antennas operating at 20 GHz, 22 GHZ, 24 GHz, 28 GHz, etc. can be designed, not limited to the above embodiments.

[0051] To better demonstrate the technical effects of the present invention, a simulation is performed below on the broadband millimeter-wave stripline planar array antenna operating at 30 GHz provided in the above embodiment.

[0052] See also Figure 8 As shown in FIG, which is a frequency curve of the return loss S11 obtained by simulation of the above embodiment, it can be seen that the above antenna achieves a return loss performance below -10dB between 28.7 and 31.3GHz, with a -10dB bandwidth of 2.6GHz, showing good broadband matching characteristics.

[0053] See also Figure 9 As shown in Figure 2, which is a graph showing the gain versus frequency obtained from the simulation of the above embodiment, it can be seen that the antenna achieves an antenna gain of over 30dB between 29 and 31GHz, and the gain at the edge level exceeds 28dB, achieving high gain across a wide frequency band.

[0054] See also Figure 10 As shown in FIG, the main polarization radiation pattern of the magnetic field plane at each frequency point obtained by the simulation of the above embodiment is shown. From this figure, it can be seen that for the center frequency point and the edge frequency point, the magnetic field plane pattern of the above antenna is very stable within the main lobe range.

[0055] See also Figure 11 As shown in the figure, it is the main polarization radiation pattern of the electric field at each frequency point obtained by the simulation of the above embodiment. It can be seen from the figure that the side lobe of the electric field pattern of the antenna obtained by the above embodiment has increased compared with the magnetic field pattern. However, it still maintains a stable main lobe gain and pointing angle. Figure 10 and Figure 11 As a result, the antenna obtained in the above embodiment has a broadband and stable radiation pattern.

[0056] Through the description of the above structure and principle, those skilled in the art should understand that the present invention is not limited to the above specific embodiments. Improvements and substitutions based on the present invention using the known technology in the art fall within the scope of protection of the present invention, which is defined by the claims and their equivalents. Any parts not described in the specific embodiments are prior art or common knowledge.

Claims

1. A broadband millimeter-wave stripline planar array antenna, comprising: A first dielectric substrate, a second dielectric substrate, and a third dielectric substrate laminated together in sequence, and metallized through-holes penetrating each of the dielectric substrates; characterized in that a first copper-clad floor is provided on the lower surface of the first dielectric substrate, a stripline power splitter copper-clad layer is provided on the lower surface of the second dielectric substrate, and a second copper-clad floor is provided on the upper surface of the second dielectric substrate; the stripline power splitter copper-clad layer, the first copper-clad floor, and the second copper-clad floor together constitute a stripline transmission line; a third copper-clad floor is provided on the upper surface of the third dielectric substrate, and second and third slots are provided on the second and third copper-clad floors, respectively, corresponding to power splitter terminals of the stripline power splitter copper-clad layer; each power splitter terminal, the corresponding second and third slots, and the metallized through-holes arranged around the periphery of the three together constitute an antenna unit; A feeding waveguide is installed at the bottom of the first dielectric substrate, a first slot without copper cladding is provided at the center of the first copper cladding layer, and a tuning patch is provided at the center of the first slot; the first slot, the stripline power splitter copper cladding layer, and the portion of the metallized through hole at the center of the first dielectric substrate together form a resonant cavity, which is used to achieve high-efficiency conversion of electromagnetic energy from the feeding waveguide to the resonant cavity and then to the stripline power splitter copper cladding layer; The second gap and the third gap are both rectangular gaps, the opening size of the second gap is smaller than the opening size of the third gap, and the orthographic projection of the second gap on the third copper clad layer floor falls within the third gap; The metallized through-hole penetrates all dielectric substrates; the portion of the metallized through-hole surrounding the second slot in the first dielectric substrate and the second dielectric substrate, together with the first copper-clad floor and the second copper-clad floor, forms a resonant cavity for realizing electromagnetic energy conversion and coupling the electromagnetic energy fed by the power splitter end to the third dielectric substrate; the portion of the metallized through-hole surrounding the third slot in the third dielectric substrate, together with the second copper-clad floor, forms an open horn for radiating the electromagnetic energy coupled from the second slot into free space, thereby realizing the conversion of radiated waves.

2. The broadband millimeter-wave stripline planar array antenna according to claim 1, characterized in that: The antenna units form a periodically arranged array of 2×2 or more.

3. The broadband millimeter-wave stripline planar array antenna according to claim 1, characterized in that: The first slot is located at the center of a contact surface between the feeding waveguide and the first dielectric substrate.

4. The broadband millimeter-wave stripline planar array antenna according to claim 1, characterized in that: The stripline power dividing copper clad layer is a power dividing network composed of multiple groups of T-shaped stripline power dividing structures with the same phase, which is used to achieve equal-phase power distribution from the middle feeding waveguide to each of the antenna units; by adjusting the size of each group of T-shaped stripline power dividing structures, unequal power distribution from the central antenna unit to the edge antenna units can be achieved.

5. The broadband millimeter-wave stripline planar array antenna according to claim 4, characterized in that: The stripline power divider copper clad layer realizes a uniform 1 dB power drop from the center antenna to the edge antenna units in the horizontal and vertical directions.

6. The broadband millimeter-wave stripline planar array antenna according to claim 1, characterized in that: It is a millimeter wave antenna operating at 20GHz to 30GHz.

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